Omron G3ZA - MANUAL 2 User Manual page 56

Detecting Heater Burnouts (4-channel Models Only)
Operation after Error
Detection
Calculating the Heater
Burnout Detection
Value
Application Examples
1. Single-phase Heaters
Example:
• Each channel's status can be read individually to check it for heater burn-
out detection.
It is possible to select the Controller's operation after a heater burnout is
detected.
For details on selecting operation after an error, refer to 4-14 Setting Opera-
tion at Error (4 and 8-channel Models) on page 53.
Use the following formula to calculate the heater burnout detection value.
Heater burnout detection value =
Note The result is an integer display.
When two or more heaters are connected through the current transformer, set
the burnout detection value to detect burnouts on the heater with the smallest
current. (If the heater currents are all the same, set the value for burnout of one
wire.)
Example 1: Using One 1-kW Heater (200 V AC)
Normal operation
5 A AC line
200 V
5 A
To CT input
If the normal heater current is 5 A and the burnout heater current is 0 A, the
heater burnout detection value is calculated as follows:
Heater burnout detection value =
(Normal current + Burnout current)
2
Burnout occurred
Wire
200 V
Load
break
0 A
CT
To CT input
(Normal current + Burnout current)
2
5 + 0
= 2.5 → 2 [A]
=
2
Section 4-5
AC line
Load
CT
39